ESD - Ecological Studies Lesson

Ecological Studies

A classical ecologic study examines the rates of disease in relation to a factor described on a population level. The units of study are populations or groups of people rather than individuals.  The population-level factor may be an aggregate measure that summarizes the individual members of the population, an environmental measure that describes the geographic location where the population resides or works or a global measure that has no analog on the individual. Ecologic studies usually identify groups by place, time, or a combination of the two. The lack of individual-level information leads to a limitation of ecologic studies known as the ecological fallacy. The ecological fallacy means that one cannot necessarily infer the same relationship from the group level to the individual level. Ecological studies can be done quickly, are inexpensive, and are easy to analyze. They have the ability to achieve a wider range of exposure levels than could be expected from a typical individual-level study. An additional limitation of ecological studies is the lack of information on characteristics that might distort the association.

[CC BY 4.0] UNLESS OTHERWISE NOTED | IMAGES: LICENSED AND USED ACCORDING TO TERMS OF SUBSCRIPTION